基于弥散与分离裂缝模型的混凝土开裂比较研究

A COMPARATIVE STUDY FOR CONCRETE FRACTURE ANALYSIS USING SMEARED-AND DISCRETE-CRACK MODEL

裂缝扩展是影响混凝土结构非线性响应的重要因素,其扩展深度与张开位移是评价结构安全性的重要指标。基于弥散裂缝框架,该文建立了等效裂缝张开位移与损伤因子、断裂带宽度之间的函数关系。分别采用弥散、分离两类裂缝模型模拟I型断裂和I-II混合型断裂试验,二者在结构承载力、裂缝扩展和裂缝张开位移方面均获得了基本一致的结果。数值算例表明弥散裂缝模型与分离裂缝模型计算精度接近但其效率更高。

Crack propagation is one of the key issues for simulating nonlinear behavior and evaluating safety of concrete structures. The equivalent crack opening displacement of smeared damage-fracture model is formulated with damage parameter and crack band width. Mode I and mixed-mode fracture tests of concrete beams are analyzed using smeared and discrete crack models. The numerical results of smeared crack model, including load-carrying capacity, crack propagating depth and equivalent crack opening displacement, are consistent with those obtained using the discrete one. The comparative study shows that these two models have almost identical accuracy in evaluating both macro-scale and meso-scale structural information, but the smeared crack model has higher computation efficiency than the discrete one.